import sys
import random

def f(lst):
    ln=len(lst)
    avg = sum(lst)/ln
    s = [(xi-avg)**2 for xi in lst]
    s = (sum(s)/(ln-1))**0.5
    return s

a=[[3,7,23,21,8,10]]
for i in range(9):
    n = random.randint(15,1000)
    l =[random.randint(1,100) for  j in range(n)]
    a.append(l)

for i  in range(10):
    fin = open('{}.in'.format(i+1),'w')
    fout = open('{}.out'.format(i+1),'w')
    print(*a[i],file=fin)
    print('{:.2f}'.format(f(a[i])),file=fout)
    fin.close()
    fout.close()
